Numerous laboratory tests for analytes of interest are performed on biological or environmental samples for diagnosis, screening, disease staging, forensic analysis, pregnancy testing, drug testing, and other reasons. However, most of these quantitative tests require the expertise of trained technicians in a laboratory setting using sophisticated instruments. Moreover, laboratory testing increases the cost of analysis and delays the results. In many circumstances, delay can be detrimental to a patient's condition or prognosis, such as, for example, the analysis of markers indicative of myocardial infarction. In these critical situations and others, it would be advantageous to perform such analyses at the point of care, accurately, inexpensively, and with a minimum of delay.
Some solutions to this problem have been developed, for example, using a disposable cartridge configured to analyze a single analyte and a portable, handheld reading apparatus configured to accept the cartridge, process the data, and present data to a user (see, e.g., U.S. Pat. Nos. 7,419,821 and 5,096,669, herein incorporated by reference in their entireties). These conventional cartridges have a single input and a single output for communicating with the reader, e.g., to transmit and receive signals for controlling the analysis and transferring the resulting data. However, many molecular tests require (or would benefit from) assessing the presence or absence of, or measuring the amount or concentration of, multiple analytes. These tests require multiple analyte sensors, each adapted to test for a single analyte in the multiple analyte panel. While cartridges can be manufactured to comprise multiple sensors for testing multiple analytes, the data collection requires obtaining real-time signals from each individual sensor. A solution to this problem would be to design cartridges and readers to have multiple communication channels, one for each sensor or analyte being tested. However, such a solution is not desirable for several reasons. First, such redesigning may require changes in the form factor (e.g., dimensions and size of the cartridges and/or reader) and/or the electronics of both the cartridges and the reading apparatus. These changes may then, in turn, require costly adjustments in manufacturing the devices and/or produce resistance among users in accepting the new system. Second, while the disposable cartridges are relatively inexpensive, the reading apparatus is relatively expensive. Thus, users will not want to purchase a new reading device to accommodate the multiple-analyte cartridges. Accordingly, the field has a need for a testing technology that provides point-of-care, real-time testing of multiple analytes using the prior installed base of reading apparatuses that comprise one input and one output channel.